In conventional strapping apparatus, paper sheets such as banknotes are bundled by the predetermined number of sheets and strapped by a strap band. An operator previously loads the strap band having a color corresponding to paper sheets (as a strapping target) into the strapping apparatus. The strapping apparatus straps the paper sheets by using the strap band (having the color corresponding to the strapping target) loaded by the operator.
However, in the strapping apparatus, if a strap band having an erroneous color is loaded, the paper sheets are strapped by using the strap band having the erroneous color (as it is), which is a problem.